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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: (x-4)*(4+x)+ x2 – 16= 3 (2x – 3)(x-6)-x*(2x+5)=6

Toán Lớp 8: (x-4)*(4+x)+ x2 – 16= 3
(2x – 3)(x-6)-x*(2x+5)=6

Comments ( 1 )

  1. Giải đáp:
    a, (x-4)(4+x)+x^2-16=3
    <=> x^2-16+x^2-16=3
    <=> 2x^2-32=3
    <=> 2x^2=35
    <=> x^2=35/2
    <=> x=+-sqrt(35/2)
    <=> x=+-(sqrt70)/2
    Vậy phương trình có nghiệm S={+-(sqrt70)/2}
    b, (2x-3)(x-6)-x(2x+5)=6
    <=> (2x^2-12x-3x+18)-(2x^2+5x)=6
    <=> 2x^2-12x-3x+18-2x^2-5x=6
    <=> -20x+18=6
    <=> -20x=-12
    <=> x=3/5
    Vậy phương trình có nghiệm S={3/5}
     

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222-9+11+12:2*14+14 = ? ( )